The invention relates to a connector for connecting welding torch, more particularly, it relates to the socket-like connecting member coupling a welding apparatus with a welding torch, which connecting member is usually mounted on the front-plate of the welding apparatus as a connector socket. The connector according to the invention comprises a connector body with a nest for the wire-guide and a nest for the gas supply conduit on the front surface of the connector body, it has one or more electric contacts situated flushed into the front surface and lead out at the rear surface of the connector body, further, it has a wire-guide intermediate piece connected to the nest for the wire-guide from the back and a lead-in leading into the nest for the gas supply conduit from the back, further, it has a threaded surface made of electrically conductive material, a contact surface beside it and a house made of insulating material surrounding the connector body from the side shaped to be suitable for mounting the connector.
Well known is the so called Binzel-type connector, having a connecting body made of brass, the weight and dimensions of which are quite significant, and the welding current is lead to the connecting body from the back using a wire-guide intermediate piece fixed in the connecting body by screw joint, and the current is connected to the wire-guide intermediate piece by a screw joint, e.g. by fixing the cable shoe of the cable carrying the current to it. The connector described in patent specification no. EP 0794 029 is also known, where the weight and the dimensions are slightly reduced due to its construction, however, it still has the disadvantage that the welding current is coupled to the connecting body providing the contact indirectly from the back through a wire-guide intermediate piece, and the current, e.g. the cable shoe of the cable carrying the current to it is connected to the wire-guide intermediate piece by a screw joint. Further, it is a disadvantage of this device as well that the connecting body carrying the nests for the electric contacts is made of electrically conductive material, as a result of which the weight of the connector is still too high.
It is a disadvantage of both constructions that the connecting body is fixed in the plastic house of the connector so as to be prevented from displacement or rotation by an additional screw joint fixing the connecting body to the house, which connection may loosen in the course of regular, normal use.
The above described disadvantages made it necessary to find a solution for the connector eliminating these disadvantages, so the weight and the longitudinal size of which is reduced as compared to the connectors described above, so that it can be mounted more easily and in a simpler way to the welding apparatus when using it, and which is easier to handle due to its lower weight, while the capacity and insulating properties of which are not worse, and further, it must be possible to fashion the connector to be interchangeable so as to ensure connectibility of the widely used connectors used for the same purpose and the units coupled to the connectors.
The fundamental idea of the invention is that the desired connector can be realised if only the part of the connector directly taking part in transmitting the welding current is made of conducting material., the current is connected to it directly, all other parts of the connector are made of non-conducting material, preferably plastic, and the conducting element and the plastic body carrying it are secured against displacement by form-fitting and/or by the joint establishing the electric connection.
Therefore the connector according to the invention comprises a connector body, a nest for the wire-guide and a nest for the gas supply conduit on the front surface of the connector body, one or more electric contacts situated flushed on the front surface and lead out at the rear surface of the connector body, a wire-guide intermediate piece connected to the nest for the wire-guide from the back and a lead-in leading into the nest for the gas supply conduit, a threaded surface made of electrically conductive material and a contact surface beside it, and a house made of insulating material surrounding the connector body from the side shaped to be suitable for mounting the connector. The essential character of the connector is that the connector body and the house is made of insulating material, preferably plastic, designed as a unit in one piece connected by a rear wall, further, it has an insert made of electrically conductive material carrying the threaded surface made of electrically conductive material and the contact surface, preferably ring-shaped contact surface, which insert can be fitted in a nest formed by the side surface of the connector body part of this unit and the surface of the house part of this unit opposite to this side surface, the insert has a part at its side surface suitable for connecting the current to it, and there is an opening on the sidewall of the house part leaving uncovered the side surface of the insert suitable for connecting the current to it, and the insert is secured rotationally in the nest by form-fitting and/or by the catching of a device connected to the side of the insert suitable for connecting the current to it in the edge of the opening.
At a preferred embodiment the insert is secured against being pulled out from the nest by the design that either the side surface of the insert suitable for connecting the current to it, or a device connected to the side surface of the insert suitable for connecting the current to it is caught in the edge of the opening.
It is an especially advantageous embodiment, where the side surface of the insert suitable for connecting the current to it is a thicker side-portion, which is fitted into the opening on the sidewall of the house part, preferably projecting out of it if the insert is in its position fitted into the nest.
In order to connect a device carrying the current to the insert, the insert suitably has a threaded hole in its thicker side-portion designed to be suitable for connecting the current to it.
At a further preferable embodiment, the thicker side-portion of the insert, suitable for connecting the current to it, fitted in the opening on the house part, projects from the lateral surface of the house part near the rear wall.
In the course of intended use, the connector is fixed in a hole on the front-plate of the welding apparatus. The solution for mounting can be a flange formed by the front wall of the house part and one or more bore-holes on the flange, by which it can be mounted on the front-plate of the welding apparatus by screw joint.
At another possible solution for mounting the connector according to the invention the house part has a flange and one or more tongues protruding from the rear wall towards the flange, in the removed position of the insert the tongue can be bent due to its flexibility towards the connector body part, if the insert is at its place the tongue is prevented from being bent, in its unbent position this tongue defines a retaining groove with the opposite surface of the flange. At this embodiment there is a projection in the end of the tongue or the end of the tongue is thickened so as to form a deeper retaining groove.
The position of the connector according to the invention is secured rotationally in the front-plate of the welding apparatus if there is a shoulder on the rear surface of the flange of the house part with a shape different from circle, and there is an opening on the front-plate receiving the shoulder in a way that the shoulder is fitting in it.
At another preferable embodiment of the connector according to the invention the insert has a cylindrical or prismatic body, preferably a quadratic prism with rounded edges, with an axial bore-hole fitting to the connector body part, and the shape of the receiving nest for the insert is fashioned in a way that the cylindrical or prismatic body is fitting in it.
The wire-guide intermediate piece of the connector according to the invention has a removable wire-guide liner in its axial bore. The wire-guide intermediate piece can be made of material that is not very good electric conductor or can be made of non-conducting material as well.
The insert is made of material of good electric conductivity, preferably copper, brass, copper alloy or other suitable conductive material.
In what follows, the essence of the invention is described in detail by presenting its preferable embodiments, with reference to the accompanying schematic drawings in which: